A conventional muscle exercising device is designed to exercise specific parts of the user's body by repeatedly operating arms (for example) to reinforce the muscles. Generally, weights are applied to increase the weight in vertical direction so that the muscles are exercised to lift the weights. Another type of the load is applied by rubber bands which have different bouncing forces and the users have to expand the rubber bands to exercise the muscles. In other words, the conventional muscle exercising devices have to be bulky for provide sufficient space for the weights or rubber bands. This is inconvenient for storage and for small gyms.